I think a clarification needs to be made here.
No matter what you do, you will end up hurting some girls simply by being moderately attractive and existing. There are girls out there who are AFChicks, and they fall for you, get oneitis, dream about you, never make a move(or the female equivalent of "a move"), and suffer heartache every time they come across you.
to rAFCs, this will sound familiar as it reflects their own experience. Perfectly nice girls (not ninja bitches) leave pain and destruction in their wake simply by existing for AFC's to moon over and suffer.
This sounds pessimistic, but the flipside is that you brighten people's days inadvertently all day without knowing it. Every time you sarge a girl, you're complimenting her and telling her that she is worth sarging (with some of you [including me] that may not be saying much, but let them think what they want).
You can't really do anything about this kind of damage you're doing.
What you can control, however, is how far you lead certain girls on. If you lie (like above), you are definitely going to hurt people. Furthermore, we're not just talking about lying in words here. Body language and tone can show attractive traits; they can also communicate interest. If you let yourself lie in that manner, then you could definitely be causing some pain here. (What if you found out that the girl you thought was "the One" was faking her IOI's?)
In the end, it all comes down to congruence. Figure yourself out before anyone else (What am I looking for? LTR? ONS? mLTR?) and then just communicate that. You'll automatically attract girls who meet your qualifications.
"Be ye therefore wise as serpents, and harmless as doves." ~ Matt. 10:16
"But it is time you recalled that, though I am a servant, I am not your servant." Vetch, A Wizard of Earthsea